Apparatus for producing synthetic yarns formed of bicomponent filaments

ABSTRACT

AN APPARATUS FOR THE SPINNING OF SYNTHERIC YARNS MADE UP OF BICOMPONENT FILAMENTS COMPRISING A FEED MEANS FOR EACH LIQUID SPINNING COMPONENT AND A SPINNING ASSEMBLY HOUSING CONNECTED TO THE FEED MEANS. THE ASSEMBLY HOUSING INCLUDES A SUBSTANTIALLY HORIZONTAL SPINNERET PLATE WITH SPINNING ORIFICES ARRANGED IN A PATTERN, A CLOSABLE ACCESS MEANS AND GUIDE MEANS FOR DIRECTING THE SPINNING COMPONENTS FROM THE FEED MEANS TO THE ORIFICES IN TSHE SPINNERET PLATE. THE GUIDE MEANS IS INSERTABLE AND REMOVABLE THROUGH THE CLOSABLE ACCESS MEANS. THE ASSEMBLY HOUSING HAS A HORIZONTAL SECTION WHICH IS OBLONG AND HAS A LENGTH WHICH IS APPROXIMATELY ABOUT ONE AND ONE HALF TO ABOUT TWO TIMES ITS WIDTH AND THE SPINNERT PLATE WHICH IS PLACED WITHIN THE ASSEMBLY HOUSING HAS, IN THE HORIZONTAL PLANE, AN OBLONG CONFIGURATION AND ALSO DIMENSIONS WHICH ARE ABOUT THE SAME ORDER OF MAGNITUDE AS THOSE OF THE ASSEMBLY HOUSING. THE ASSEMBLY, IN THIS MANNER, PROVIDES A RIGID COMPACT CONSTRUCTION THAT PROMOTES RAPID AND UNIFORM HEAT TRANSFER TO THE SPINNING COMPONENTS WITHIN THE HOUSING UPON BEING PLACED IN A HEATED JACKET OR THE LIKE.

971 P. v. M. VAN DEN BIGGELAAR ET AL 3,559,237

' APPARATUS FOR PRODUCING SYNTHETIC YARNS FORMED OF BICOMPONENT FILAMENTS Filed Nov. 22, 1967 6 Sheets-Sheet 1 INVENTORS p404 M76271 AMP/z Willi/M244? 1 /4A/ cam/[1A9 PAM/44!? W M ORNEY 1971' P. v. Mh-VAN DEN BIGGELAAR ET 3,559,237

F0 PR APPARATUS ODUCING SYNTHETIC YARNS FORMED OF v BICOMPONENT FILAMENTS Filed Nov. 22, 1967 6 Sheets-Sheet 2 I g /7 I 6 5 v L l O Q29 /3A?\\ 0 363. 0 5 an 35 360 .59

V\L\\\\\\\\\\%N\\\\\\\\\\ 5 fl. L?

ATTORNEY "1 1 P. v. M. VAN DEN BIGGELAAR ETAL 3,559,237

I APPARATUS FOR PRODUCING SYNTHETIC YARNS FORMED 0F BICQMPONENT FILAMENTS Filed Nov.- 22. 1967 6 Sheets-Sheet 5 INVENTORS 3,559,237 D OF 6 Sheets-Sheet 4 INVENTORS PAUL V/MfiIfIIW/[MIDAW 676645144X P- V. M. VAN DEN BIGGELAAR ETA]- FOR PRODUCING SYNTHETIC YARNS FORME BICOMPONENT FILAMENTS .14 mam/ 14/614 BY w M ATTORNEY Feb. 2, 97 P. v. M. VAN DEN BIGGELAAR ETAI- 3,559,237

APPARATUS FOR PRODUCING SYNTHETIC YARNS FORMED OF BICOMPQNENT FILAMENTS Filed Nov. 22, 1967 6 Sheets-Sheet 5 INVENTORE BYMWM ATTORNEY Feb. 2, 1971 Pi. v. M. VAN DEN BIGGELA'AR ETA!- 3,559,237

I APPARATUS FOR PRODUCING SYNTHETIC YARNS FORMED 0F MW m INVENTORS OZ W/VC'EA/I'MAP/[WV United States Patent 3,559,237 APPARATUS FOR PRODUCING SYNTHETIC YARNS FORMED 0F BICOMPONENT FILAMENTS Paul V. M. van den Biggelaar, Dieren, Gelderland, and Jan C. Rijkaart, Arnhem, Netherlands, assignors to American Enka Corporation, Enka, N.C.

Filed Nov. 22, 1967, Ser. No. 685,049 Claims priority, application Netherlands, Nov. 23, 1966,

616462 Int. Cl. D01d U.S. Cl. 18-8 23 Claims ABSTRACT OF THE DISCLOSURE An apparatus for the spinning of synthetic yarns made up of bicomponent filaments comprising a feed means for each liquid spinning component and a spinning assembly housing connected to the feed means. The assembly housing includes a substantially horizontal spinneret plate with spinning orifices arranged in a pattern, a closable access means and guide means for directing the spinning components from the feed means to the orifices in the spinneret plate. The guide means is insertable and removable through the closable access means. The assembly housing has a horizontal section which is oblong and has a length which is approximately about one and one half to about two times its width and the spinneret plate which is placed within the assembly housing has, in the horizontal plane, an oblong configuration and also dimensions which are about the same order of magnitude as those of the assembly housing. The assembly, in this manner, provides a rigid compact construction that promotes rapid and uniform heat transfer to the spinning components within the housing upon being placed in a heated jacket or the like.

The invention relates to an apparatus for the spinning of synthetic yarns formed by bicomponent filaments and more particularly to a spinning assembly housing having access means for changing the internal structure of the housing to produce various types of bicomponent filaments, and a rigid compact construction with an oblong configuration that promotes rapid and uniform heat transfer to the polymeric components to be spun within the housing.

An apparatus of a type similar to that of this invention is known. The known apparatus comprises an assembly housing and a spinneret plate with horizontal sections that are circular. For some purposes the known apparatus is quite satisfactory. But it has been found that especially in the case of melt spinning bicomponent yarn, where the assembly housing is placed in a heated jacket, the known apparatus shows a number of drawbacks.

In the first place, the known apparatus requires a lot of room, which is costly and often not available. In the second place, the known apparatus is less suitable to be used for the simultaneous spinning of two polymers at high pressures of, for instance, 200 to 500 kg./cm. and with a high viscosity, because the internal cylindrical wall surface of the assembly housing is very large. Consequently, large forces are produced and a relatively heavy and costly construction is required. In the third place, it has been found that with the known apparatus it is not possible to satisfy, particularly in the case of the bicomponent spinning process, the present high demands as regards rapid and uniform heat transfer from the heated jacket via the assembly housing to the two polymer components to be spun.

Patented Feb. 2,, 1971 Advantageously this invention provides an apparatus which does not show the afore-mentioned disadvantages.

Thus, this invention contemplates an apparatus for the spinning of synthetic yarns formed of bicomponent filaments, which comprises feed means for each of the liquid components to be spun and a spinning assembly housing connected to said feed means, the assembly housing ineluding a substantially horizontal spinneret plate with spinning orifices arranged in a pattern, a closable access means, and guide means for directing the spinning components from the feed means to the orifices in the spinneret plate, the guide means being insertable and removable through said closable access means and the horizontal section of the assembly housing being oblong and preferably rectangular and having a length which is at least approximately about one and a half to about two times its width. Also the spinning plate which is placed in the assembly housing has in the horizontal plane an oblong configuration or circumference with dimensions which are of about the same order of magnitude as those of the assembly housing.

In this way a simple, compact construction may be obtained, and a rapid and uniform heat transfer from a heated jacket via the assembly housing to the two components to be spun can be realized.

When the apparatus of this invention is provided with a mixer having stationary guiding members, it has been found advantageous to provide a mixer in the assembly housing that is located over the spinneret plate and that has a mixing channel or mixing channels which extend substantially in a horizontal direction.

The apparatus according to the invention is particularly suitable for the manufacture of industrial yarns, i.e., yarns having a high total denier, since in that case the invention makes it possible with simple means to keep the occurring forces and the dimensions between acceptable limits.

According to a preferred embodiment of the apparatus of this invention the mixer is also oblong and positioned over the spinneret plate and opposite the closable access means including a (dis)mounting hole or access opening and sealing means in the short side of the assembly housing. According to the invention the mixer advantageously consists of a bipartite block in the dividing plane of which the mixing channel (or the mixing channels) with stationary guiding members is (are) located. Furthermore, when the dividing plane of the mixer in the assembly housing is placed horizontal and the two parts of the mixing block'are attached to each other by means of practically vertical bolts and the underside of the mixing block is made to rest on the upper side of the spinneret plate, then these bolts and also the mixing block are less heavily loaded.

By preference the apparatus according to the invention is characterized in that in the direction of flow of the liquid to be spun, the mixing channel, which is entirely or partially filled with guiding members, is substantially in the shape of a rectangle.

A particularly effective embodiment is obtained when the feed channels of each of the two components end downwards into the rectangular mixing channel at various points and, after they have reunited, collectively end at one point in the mixing channel, and the outlet of the mixing channel communicates with a downwardly sloping channel which opens into a distribution space for the spining liquid positioned over the spinneret plate.

In the apparatus of the invention the guiding members of the mixer are advantageously so constructed that they cause the number of layers of the spinning liquid repeatedly to double so that the two components are finely intermixed.

According to the invention it has surprisingly been found that the oblong spinning assembly for bicomponent spinning also may be made suitable in a simple manner for the spining of bicomponent yarn with a side-by-side or sheath-core configuration of the two components in the single filaments. To this end the apparatus of the invention must be so constructed that in the assembly housing the feed channels for each of the two components run separately to practically as far as the points where the channels feed the spinning liquid components into the spinning orifices.

According to a preferred embodiment of the apparatus, the separate feed channels for each of the components are provided in the assembly housing in a number of oblong feed plates positioned one over the other and over the spinneret plate. The feed plates provided with separate channels are advantageously located in the assembly housing so that they are opposite the closable (dis)mounting hole or access opening in the short side of the assembly housing.

In the apparatus according to the invention the feed channels in the feed plates for the one component extend downwardly near the outer circumference of the feed plates, and the feed channels for the other component extend downwardly inwardly from the channels for the one component. Advantageously bicomponent yarn of the side-by-side type may be made with an apparatus which is further characterized in that the feed channels for the one component, after they have reached the spinneret plate, horizontally so extend in the underside of the lowermost feed plate over the spinneret plate that each of said feed channels covers at least two adjacent spinning orifices, and the feed channels for the other component in the lowermost feed plate are formed by a large number of bores which each end over two adjacent orifices in the spinneret plate.

Bicomponent yarn of either the sheath-core type or of the side-by-side type may with advantage be made with an apparatus which is characterized in that the feed channels for the one component, after they have reached the spinneret plate, run into a horizontal distribution space extending over the spinneret plate, and the feed channels for the other component in the lowermost feed plate are formed by a large number of bores which each end over a single corresponding spinning orifice in the spinneret plate.

The invention will be further described with reference to the accompanying schematic drawings in which,

FIG. 1 shows a longitudinal section taken along the line II in FIG. 2 of an embodiment of a spinning assembly according to the invention;

FIG. 2 shows a cross-section of the assembly taken along the line IIII in FIG. 1;

FIG. 3 shows a sectional view taken along the line IIIIII in FIG. 1;

FIGS. 4a to 46 are end, side, top and bottom views of a combination of stationary guiding members;

FIG. 5 shows a longitudinal section of the construction of a spinning assembly for the manufacture of bicomponent yarns with filaments of the side-by-side type;

FIG. 6 shows a cross-section of the side-by-side type assembly taken along line VI-VI in FIG. 5;

FIG. 7 shows a sectional view of the side-by-side type assembly taken along line VIIVII in FIG. 5;

FIG. 8 shows a single filament of the side-by-side type in cross-section.

FIGS. 9, 10 and 11, respectively, show different sectional views of the construction of a spinning assembly for the manufacture of bicomponent yarns with filaments of the sheath-core type;

FIG. 12 shows a single filament of the sheath-core type in cross-section;

'FIG. 13 shows diagrammatically a modification of an assembly housing for the manufacture of bicomponent yarns with filaments of the side-by-side type; and

FIG. 14 shows a section taken along the line XIV XIV in FIG. 13.

FIGS. 1 to 3 show only that part of an apparatus for the melt spinning of a bicomponent yarn that is of importance to the present invention, namely: the spinning assembly. The assembly housing 1 and the spinneret plate 2 have a rectangular horizontal section. The spinneret plate 2 is provided with a large number of spinning orifices 3 which are arranged in a pattern, the outer boundary of which is also rectangular. The spinneret plate 2 rests on a shoulder 4 in the housing 1, a packing ring 5 being provided between the shoulder and the spinneret plate. In a space over the spinneret plate 2 there is a filter gauze pack 6.

In either of the short sides of the housing 1 there is a closable (dis)mounting hole 7, the height of which is designated by reference numeral *8 and the width by reference numeral 9.

On the spinneret plate 2 rests the mixer which consists of a lower block 10 and an upper block 12 secured thereto with bolts 11. The openings 7 are closed on the outside by sliding covers 13. Between each sliding cover 13 and the mixer (10, 12) there are successively provided, in an inward direction, an end ring 14, a packing ring 15, and a gland 16. The packing ring may already be deformed before the start of the spinning process by means of a cap screw 17 provided with an end ring 18.

The assembly shown in the drawings is meant for the spinning of bicomponent yarn. In the housing 1 there are therefore provided two feed lines 19 and 20, so that each of the two polymeric components may be supplied under high pressure through a gear pump (not shown). From the feed lines 19 and 20 each of the components can flow downwards via the respective filter gauze packs 21 and 22 and the respective distribution plates 23 and 24. The distribution plates 23 and 24 each rest on the upper side of the upper block 12 of the mixer, and between each distribution plate and the upper block there is provided a packing ring 25, 26.

The distribution plates are provided with a large number of perforations 27. Under each of the distribution plates 23, 24 there are in the upper block 12 of the mixer funnel-shaped collecting chambers 28 and 29, which at their bottom ends communicate with horizontal channels 30 and 31, respectively, and in which the two components can flow towards each other in the directions indicated by the arrows 32 and 33, respectively. When the two components have met they can collectively flow in the direction indicated by the arrow 34 through the channel 35 to the beginning of the mixing channel indicated by reference numeral 36, which mixing channel has a square cross-section (see FIG. 2). The mixing channel 36 is approximately rectangular (see FIG. 3) and is partially filled with guiding members 37, which are indicated in FIG. 3 by a cross.

The two components can flow through the mixing channel 35 in the directions indicated by the successive arrows 38, 39, 40, 41, 42, 43, 44 and 45. As a result of the mixing action of the guiding members the number of layers of the two components are repeatedly doubled so that the materials are finely intermixed.

FIGS. 4a to 4e are various views of an embodiment of a combination of stationary guiding members having a satisfactory mixing action. FIG. 4a is a view of the end face of the combination of guiding members. This combination consists in principle of a bar having a square cross-section and recesses in its side walls. In FIG. 4a the arrows b, c, d and e, indicate the directions in which the side elevations shown by the FIGS. 4b, 4c, 4d and 4e, are viewed. In the FIGS. 4a to 4e the parts where no material is removed are hatched. The shape of the recesses is obtained by making a zig-zag groove at constant depth in each of the side walls by means of an end mill. The path of the molten spinning material through the grooves is shown by the lines 46, 47, 48 and 49. In the mixing channel 36 a suitable number of guiding members may be provided. It should be recog nized that a mixer of this type per se is known.

In FIG. 3 the reference numeral 50 designates the end of the rectangular mixing channel 36. From the end 50 the mixed polymer can flow downwards through the inclined channel 51 in the direction indicated by the arrow 52 (see FIG. 2), after which the polymer can distribute itself over the filter gauze pack 6 and can leave the spinning assembly through the spinneret plate 2 provided with orifices 3.

On the housing 1 there are ears or lugs 53, 54 with the aid of which the assembly housing can be placed in 1 a heated jacket (not shown) or removed therefrom. Moreover, in the housing 1, over the center of the distribution plates 23 and 24, there are provided plugs 55 and 56, respectively, which may be removed for the purpose of withdrawing the respective distribution plates and filter gauze packs. The plugs are provided using a construction indicated as a whole by the reference numeral 57, which, however, it will be appreciated does not affect the essence of the invention.

From the drawings (FIGS. 1 to 3) it can be seen that the dimensions of the openings 7 are such that the mixer formed by the lower block 10 and the upper block 12 can entirely be removed from or placed back into the assembly housing through one of the openings 7. Also the other parts present in the housing 1, such as the spinneret plate 2 with filter gauze pack 6, and the distribution plates 23, 24 with respective filter gauze backs 21, 22 can be Withdrawn or replaced through the relatively small openings 7 in the short side walls of the housing 1. Consequently, the relatively large assembly can in a simple manner be given a very rigid construction.

FIGS. 5, 6, 7, 9, 10 and 11 are sectional views of two bicomponent-spinning assemblies in which no mixers are present, like parts shown in FIGS. 1, 2 and 3 being referred to by like reference numerals. The FIGS. 6 and 7 are sectional views along the respective lines VI-VI and VII-VII in FIG. 5. The FIGS. 10 and 11 are sectional views along the lines XX and XI-XI in FIG. 9.

In the assembly according to the FIGS. and 7 as well as that shown in the FIGS. 9 to 11 the two polymer components can flow down from the funnel-shaped collecting chambers 28 and 29 to approximately the level of the upper side of the spinneret plate 2 through entirely separated systems of feed channels 58, 59 for the right hand (viewed in the plane of the drawing) polymer component and channels 60, 61, 62, 63, 64 for the left hand component. The feed channels 58 to 64 for the two components are located in three feed plates 65, 66 and 67 positioned one above the other and over the spinneret plate 2. These feed plates are further so positioned in the assembly housing 1 that they are opposite the closable (dis)mounting hole 7 in the short side of the assembly housing 1. The feed channels 59 for the one polymer component, fed to the right hand upper side of the assembly, extend downwards near the outer circumference of the plates 65, 66 and 67, and the feed channels 61, 62, 63, 64 for the other polymer component extend downwardly inwardly from the channels 59.

nels 59, is horizontally distributed over the spinneret,

plate 2 by a large number of obliquely placed horizontal channels which extend across the lower side of the plate 67 and each cover at least two adjacent spinning orifices 3. With such an embodiment the two polymer components each practically fill one half of each spinning orifice 3, as a result of which filaments of the side-by-side type of FIG. 8 are formed.

The assembly according to the FIGS. 9, 10 and 11 is meant for the manufacture of bicomponent yarns of the sheath-core type, of which one filament is shown in cross-section in FIG. 12. Here the one component is indicated by 71 and the other by 72. Each of the vertical feed channels 64 in the lower-most feed plate 67 is provided with a narrow outflow opening which ends over the center of a single corresponding spinning orifice 3. The polymer component which has flowed downwardly through the vertical channels 59 can distribute itself over the upper surface of the spinneret plate 2 through recesses provided in said surface and flow into spinning orifices 3 at the outer circumference thereof. With such a construction of the spinning assembly the one polymer component forms the core, and the other the sheath surrounding said core.

It will be appreciated that in accordance with this invention, many combinations of spinning components may be used to prepare the bicomponent filaments. The most appropriate combination will depend on the intended application. Exemplary of some possible combinations of the components are nylon and polypropylene, nylon and polyester, polypropylene and polyethylene, nylon and polystyrene, polyester and polystyrene, polyacrylonitrile and polvinyl alcohol, nylon and polyvinyl alcohol, and the like.

FIGS. 13 and 14 show diagramatically how the assembly according to the embodiment shown in FIGS. 9, 10 and 11 can, by a small modification, be made suitable for manufacture of biocomponent yarns of the side-by-side type. In the embodiment according to FIGS. 13 and 14, the feed channels 64 debouch eccentrically over the associated spinning orifices 3 in plate 2. In this construction, the spinning orifices are partly covered, at their upper sides, by the outlets of the feed channels for the other component.

While the novel features of the invention have been shown and described and are pointed out in the appended claims, it is to be understood that various omissions, substitutions and changes in construction and arrangement of the features shown and described may be made by those skilled in the art without departing from the spirit and scope of the invention.

What is claimed:

1. An apparatus for the spinning of synthetic yarns formed of bicomponent filaments Which comprises feed means for each of the liquid components to be spun and a spinning assembly housing connected to said feed means, the horizontal section of said housing having an oblong shape and said assembly housing including a substantially horizontal spinneret plate with spinning orifices arranged in a pattern, said plate resting on a shoulder formed in the housing, a closable access means located in a short side of the assembly housing and guide means for directing the spinning components from the feed means to the orifices in the spinneret plate, said guide means resting on the upper side of the spinneret plates; said spinneret plate and said guide means each being insertable and removable through said closable access means, and the horizontal section of the assembly housing having a length which is at least approximately about one and a half to about two times its width whereby said assembly housing provides a rigid compact constrnction that promotes rapid and uniform heat transfer to the spinning components Within said housing when the housing is heated externally.

2. The apparatus of claim 1, in which said guide means includes a mixer with stationary guiding members, said mixer being located over the spinneret plate in the assembly housing.

3. The apparatus of claim 2, in which the mixer has at least one mixing channel that extends substantially in a horizontal direction.

4. The apparatus of claim 2, in which said closable access means include an access opening and an associated sealing means located in the short side of the assembly housing, said mixer also being oblong and being positioned opposite said access opening.

5. The apparatus of claim 4, in which said mixer has a short end face with a surface area which is of the same order of magnitude as that of the access opening.

6. The apparatus of claim 2, in which the mixer consists of a bipartite mixing block and said mixing channel with the stationary guiding members is located in the dividing plane of said block.

7. The apparatus of claim 6, in which the dividing plane of the mixer is placed horizontally in the assembly housing.

8. The apparatus of claim 7, in which the two parts of the mixing block are attached to each other by practically vertical connecting means.

9. The apparatus of claim 3 in which the mixing channel, which is at least partially filled with guiding members, is, in the direction of flow of the liquid component to the spun, substantially in the shape of a rectangle.

10. The apparatus of claim 9, in which the feed means of each of the two components extend downwardly to the rectangular mixing channel at various points and the guide means provides channels arranged to collectively end at one point in the mixing channel, and the mixing channel has an outlet that communicates with a downwardly sloping channel which opens into a distribution space for the spinning components positioned over the spinneret plate.

11. The apparatus of claim 6, in which the feed means for each of the components includes a separate distribution plate and a filter, said distribution plates each being located in a space provided in the upper part of the assembly housing, and the undersides of distribution plates resting on the mixing block via sealing rings.

12. The apparatus of claim 2, in which the guiding members of the mixer are constructed to effect the number of layers of the spinning liquid components repeatedly 'be doubled so that the two components are finely intermixed.

13. The apparatus of claim 1, in which the guide means provide feed channels for each of the two components in the assembly housing that extend separately substantially to the points where said channels feed the spinning liquid components into the spinning orifices.

14. The apparatus of claim 13, in which the feed means for each of the components includes a separate distribution plate and a filter and said guide means comprise a number of oblong feed plates positioned one over the other and over the spineret plate, said plates having the separate feed channels formed therein.

15. The apparatus of claim 14, in which said feed plates are positioned in the assembly housing opposite the closable access means.

16. The apparatus of claim 13, in which the feed channels in the feed plates for the one component extend downwardly near the outer circumference of the feed plates, and the feed channels for the other component extend downwardly inwardly from the channels for the one component.

17. The apparatus of claim 16, in which the feed channels for the one component, after extending to the spinneret plate, extend horizontally in the underside of the lowermost feed plate over the spinneret plate so that each of said feed channels covers at least two adjacent spinning orifices, and the feed channels for the other component in the lowermost feed plate are formed by a large number of bores that each terminate over two adjacent spinning orifices in the spinneret plate.

18. The apparatus of claim 16, in which the feed channels for the one component, upon reaching a zone just above the spinneret plate, run into a horizontal distribution space extending over the spinneret plate, and the feed channels for the other component in the lowermost feed plate are formed by a large number of bores which each end over a single corresponding spinning orifice in the spinneret plate.

19. The apparatus of claim 1, in which the assembly housing is rectangular in shape.

20. The apparatus of claim 1, in which the spinning plate, placed within the housing assembly, has in the horizontal plane, an oblong circumference with dimensions which are about the same order of magnitude as those of the assembly housing.

21. The apparatus of claim 18, in which the feed channels for the other component in the lowermost feed plate substantially end over the centers of the spinning orifices.

22. The apparatus of claim 18, in which the feed channels for the other component end eccentrically over the associated spinning orifices.

23. The apparatus of claim 22, in which the feed channels for the other component partly cover the rims of the spinning orifices at the upper sides thereof.

References Cited UNITED STATES PATENTS 2,881,474 4/1959 Sellers et al. l8-8 3,130,448 4/1964 Tomlinson 188X 3,245,113 4/1966 Sulich 18-8 3,320,633 5/1967 Cancio et al. 18-8 3,375,548 4/1968 Kido et al. 18-8 3,387,327 6/1968 Privott et al. 188 3,397,427 8/1968 Burke et al. 188

FOREIGN PATENTS 621,433 8/ 1962 Belgium. 885,358 12/1961 Great Britain. 1,458,898 10/ 1966 France.

H. A. KILBY, 11"., Primary Examiner US. Cl. X.R. 264-471 

